While Sept. 11, 2001, is forever etched in the memory of virtually every American, far fewer remember Oct. 25, 1999. On that day, professional golfer Paine Stewart's Learjet crashed into a South Dakota field, killing all on board.

After taking off from Orlando, Fla., Stewart's plane missed a scheduled turn above Gainesville. Soon after, according to a CNN.com article, the air traffic controllers (ATC) tried to reestablish communications with the plane, but to no avail. Apparently, the plane had lost cabin pressure, incapacitating all on board.

From the official National Transportation Safety Board crash report, after a 9:19 a.m. takeoff, the pilot failed to respond to a command at 9:33. For about five minutes, the ATC tried to regain contact with the plane, and, having failed to do so, the controller immediately called the military.

According to Federal Aviation Administration regulations, every commercial jet is required to follow Instrument Flight Rules. Whenever an aircraft deviates from its normal path, a real danger could exist, as these scheduled paths are what prevent midair collisions. FAA regulations in effect on Sept. 11 spelled this out clearly.

The regulation states: "Consider that an aircraft emergency exists ... when ... there is unexpected loss of radar contact and radio communications with any ... aircraft."

It goes on to state that whenever a controller is in doubt, he or she should treat it seriously: "If you are in doubt that a situation constitutes an emergency or potential emergency, handle it as though it were an emergency."

Such protocols were clearly followed on Oct. 25 in the Paine Stewart case and on 67 separate occasions where military fighters were "scrambled" (alerted and sent to the scene) at the first sign of trouble. Within minutes of the Learjet's non-response, steps were taken to secure the aircraft.

On Sept. 11, the situation began in a similar way. According to a CNN.com timeline, after taking off at 7:59 a.m., American Airlines Flight 11 stopped transmitting its transponder beacon at 8:20. Soon after, the aircraft veered drastically off course to the northwest. According to an MSNBC article, this situation is very serious.

"Pilots are supposed to hit each fix with pinpoint accuracy," the article stated. "If a plane deviates by 15 degrees, or two miles from that course, the flight controllers will hit the panic button. They'll call the plane, saying, ‘American 11, you're deviating from course.' It's considered a real emergency, like a police car screeching down a highway at 100 mph."

One would expect a timely response by the FAA, notifying the North American Aerospace Defense Command (NORAD) of the situation quickly. Yet, according to the same CNN.com timeline, NORAD was not notified of the hijacked plane until 8:38 a.m., a full 18 minutes after the transponder signal was first lost. This stands in stark contrast to the mere five-minute response time in the situation of Stewart's Learjet.

According to a New York Times article, at 8:24, pilot John Ogonowski activated the talk-back button on Flight 11, allowing the Boston ATC to hear the hijacker's words.

"Everything will be OK," the hijacker said. "If you try to make any moves you'll endanger yourself and the airplane. Just stay quiet."

After hearing this, the controller concluded he was dealing with a hijacking situation.

A minute later, the Boston ATC notified the other air traffic control centers that Flight 11 was hijack-confirmed, but NORAD still remained in the dark for another 13 minutes.

When NORAD was finally notified of the hijackings at 8:38, it scrambled two F-15s from Otis Air National Guard (ANG) base in Massachusetts, which were in the air by 8:52. In a Cape Cod Times article, an Otis spokeswoman said that an F-15 departing from Otis can reach New York City airspace in 10 to 12 minutes.

Lt. Col. Timothy Duffy, an Otis ANG pilot sent to intercept the hijacked planes didn't doubt for one moment that there was a clear and present danger.

"It just seemed wrong," he said. "I just wanted to get there. I was in full-blower all the way."

"Full-blower" refers to the maximum possible speed a fighter jet can reach, which for the F-15 is approximately 1,875 mph, according to Air Force News. Even at 1,600 mph, they could have reached New York in seven minutes, arriving at about 8:59. Traveling even slower, at 1,125 mph, the aircraft would have reached its destination by 9:02. Either of these speeds, both well below "full-blower," would have put the fighters in position to intercept United Airlines Flight 175 before it hit the south tower of the World Trade Center at 9:02.

Upon the second collision, though, the F-15s were still 70 miles away, not to arrive until 9:11. Taking 19 minutes to travel approximately 200 miles, the intercepting jets were averaging less than 600 miles per hour.

Why would Boston ATC wait 14 minutes to notify NORAD after knowing Flight 11 was far off course, realizing transponder contact was lost, and hearing the very words of the terrorists? Why did the F-15s out of Otis take 19 minutes to travel 200 miles?

Was America unprepared for a Sept. 11 attack, or could it have been prevented by adhering to rules already in place?